EW/FS/WW/AT4
Waste water treatment
Ocean outfalls: Headworks - Overview
The headworks is the link between the receiving waste waters and the marine discharge
system and main ‘functions’ of the headworks are:
Ensure the effluent, which is to be discharged, complies with the design quality criteria.
Provide sufficient ‘head’, using pumps or gravity, to discharge the effluent according to the
hydraulic and environmental design criteria.
The headworks can include the entire treatment processes (preliminary to advanced
treatment) or can be the receiver of effluents already treated at distant treatment works.
An outfall system normally has one of the following gravity / pump systems, illustrated
below:
Gravity system
Gravity / pump system
Where only preliminary treatment is applied for an ocean outfall
(providing that offshore dilution and dispersion are sufficient ensure
compliance to water quality objectives), an ocean outfall is a viable option
when considering the real estate value of and the limited area available
along the coastal zone. The headworks of the Green Point outfall (Cape
Town) is underneath the historical Green Point lighthouse (Photo)
However, it must be kept in mind that the DWAF policy for discharging
waste water to the marine environment, stipulates primary treatment as a
minimum requirement for new outfalls.
Contact: ewisa@wamsys.co.za URL: www.waterinfo.co.za
Prepared by: eWISA
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